import graph;
import olympiad;
pen p = linewidth(0.2mm);
defaultpen(fontsize(10));



real scale =20;

pair C =(0,0);
pair A=(0,scale*sqrt(13));
pair B=(scale*sqrt(13),0);

real a = atan(2/3);

pair D=(scale*2*cos(a),scale*2*sin(a));



label("$A$",A,N);
label("$C$",C,S);
label("$B$",B,S);
label("$D$",D,NE);


draw(A -- C -- B -- D -- cycle,p);
draw(C -- D,p);

// draw perpendicular lines
/*
draw(C+(0,3) -- C+(3,3) -- C+(3,0));
draw(D+(A-D)/scale -- D+(A-D+3/2*(C-D))/scale -- D+3/2*(C-D)/scale);
*/

draw(rightanglemark(C,D,A,100));
draw(rightanglemark(A,C,B,100));